Concept explainers
Compare and contrast the roles of a corepressor and an inducer in negative regulation of an operon.
To compare: The functions of a corepressor and an inducer in negative regulation of an operon.
Introduction: Gene regulation is the process through which the cells control the expression of genes. It controls genes that are expressed to form a specific functional protein depending on the cell type. There are mechanisms that control gene expression at different levels.
Explanation of Solution
Operon contains coding DNA sequences, regulatory DNA sequences, and the regulatory proteins. Regulatory proteins act as both activators (TURN ON) and repressors (TURN OFF) of genes.
The similarities between corepressor and an inducer in negative regulation of an operon are as follows:
- Both are small molecules that bind to the repressor protein present in an operon, causing the repressor to change its shape.
The differences between the roles of a corepressor and an inducer in negative regulation of an operon are as follows:
Characteristics | Corepressor | Inducer |
Role in negative regulation of an operon |
A corepressor binds to the repressor protein, activates it to bind to the operator, and thereby inhibits transcription. For example, tryptophan acts as a corepressor in a trp operon. |
The binding of an inducer to the repressor protein makes it inactive and allows transcription of operon genes. For example, allolactose acts as an inducer in lac operon and binds to the lac repressor; hence, it cannot bind to the operator. |
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- Describe how the components of the trp operon system are affected by a mutation in trpC? Why is it that once enviornmental tryptophan is inserted into the cell, only the trp repressor is activated (turned on)?arrow_forwardUse the lac operon to describe the process of controlling transcription through operons (structural gene, operator (vs. promoter), inducer, repressor, regulatory gene)arrow_forwardIf you add a co-eepressor to a repressor protein and that allows it to bind the operator is this a inducible, constitutive or repressible operon?arrow_forward
- Draw a schematic diagram showing the components involved in the regulation of the tryptophan operon.arrow_forwardExplain how the trp operon is regulated by trp repressor and by attenuation.arrow_forwardFor the following types of transcriptional control, indicate whether the protein produced by the regulator gene will be synthesized initially as an active repressor or as an inactive repressor. Q. Negative control in a repressible operonarrow_forward
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- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning